Date: Tue, 24 Oct 2000 12:54:29 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: Tor.Egge@fast.no Cc: jwd@FreeBSD.ORG, freebsd-current@FreeBSD.ORG, peter@FreeBSD.ORG Subject: Re: newfs/fsck problem (bad superblocks) Message-ID: <Pine.BSF.4.21.0010241241280.2027-100000@besplex.bde.org> In-Reply-To: <200010220822.KAA59278@midten.fast.no>
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On Sun, 22 Oct 2000 Tor.Egge@fast.no wrote:
> > Reverting src/sbin/newfs/mkfs.c to revision 1.29 fixes
> > the problem.
> >
> > With just a quick review of the patch, I'm not sure I
> > understand what forces the last dirty buffer to be
> > written.
This worried me too.
> Try the enclosed patch. It flushes the dirty buffer before
> program exit and before reading blocks.
There are still some serious (?) overflow bugs.
Index: mkfs.c
===================================================================
RCS file: /home/ncvs/src/sbin/newfs/mkfs.c,v
retrieving revision 1.29
retrieving revision 1.30
diff -c -2 -r1.29 -r1.30
*** mkfs.c 1999/08/28 00:13:50 1.29
--- mkfs.c 2000/10/17 00:41:36 1.30
...
***************
*** 1341,1344 ****
--- 1347,1381 ----
}
if (Nflag)
+ return;
+ done = 0;
+ if (wc_end == 0 && size <= WCSIZE) {
+ wc_sect = bno;
+ bcopy(bf, wc, size);
+ wc_end = size;
+ if (wc_end < WCSIZE)
+ return;
+ done = 1;
+ }
+ if (wc_sect * sectorsize + wc_end == bno * sectorsize &&
^ overflow ^ overflow
+ wc_end + size <= WCSIZE) {
+ bcopy(bf, wc + wc_end, size);
+ wc_end += size;
+ if (wc_end < WCSIZE)
+ return;
+ done = 1;
+ }
+ if (wc_end) {
+ if (lseek(fso, (off_t)wc_sect * sectorsize, SEEK_SET) < 0) {
^^^^^^^ must cast like this to prevent overflow
+ printf("seek error: %ld\n", (long)wc_sect);
+ err(35, "wtfs - writecombine");
+ }
+ n = write(fso, wc, wc_end);
+ if (n != wc_end) {
+ printf("write error: %ld\n", (long)wc_sect);
+ err(36, "wtfs - writecombine");
+ }
+ wc_end = 0;
+ }
+ if (done)
return;
if (lseek(fso, (off_t)bno * sectorsize, SEEK_SET) < 0) {
Bruce
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